Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.Closeable;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.PriorityQueue;
import java.util.Queue;

public class Main {
	static ContestScanner in;
	static Writer out;
	public static void main(String[] args) {
		Main main = new Main();
		try {
			in = new ContestScanner();
			out = new Writer();
			main.solve();
			out.close();
			in.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	void solve() throws IOException {
		int h = in.nextInt();
		int w = in.nextInt();
		int[][] map = new int[h][w];
		for(int i = 0; i < h; i++) {
			for(int j = 0; j < w; j++) {
				map[i][j] = in.nextInt();
			}
		}
		
		int hormin = 0;
		int[] hor = new int[w];
		for(int j = 1; j < w; j++) {
			hor[j] = hor[j - 1] + (map[0][j] - map[0][j - 1]);
			hormin = Math.min(hor[j], hormin);
		}
		int vermin = 0;
		int[] ver = new int[h];
		for(int j = 1; j < h; j++) {
			ver[j] = ver[j - 1] + (map[j][0] - map[j - 1][0]);
			vermin = Math.min(ver[j], vermin);
		}
		int[][] sim = new int[h][w];
		for(int i = 0; i < w; i++) {
			hor[i] += -hormin;
			for(int j = 0; j < h; j++) {
				sim[j][i] += hor[i];
			}
		}
		for(int i = 0; i < h; i++) {
			ver[i] += -vermin;
			for(int j = 0; j < w; j++) {
				sim[i][j] += ver[i];
			}
		}
		int diff = map[0][0] - sim[0][0];
		for(int i = 0; i < h; i++) {
			for(int j = 0; j < w; j++) {
				if(map[i][j] != sim[i][j] + diff) {
					out.println(-1);
					return;
				}
			}
		}
		if(h > w) {
			for(int i = 0; i < w; i++) {
				hor[i] += diff;
			}
		} else {
			for(int i = 0; i < h; i++) {
				ver[i] += diff;
			}
		}
		
		int sum = Arrays.stream(hor).sum() + Arrays.stream(ver).sum();
		out.println(sum);
		for(int i = 0; i < w; i++) {
			for(int j = 0; j < hor[i]; j++)
				out.println("col " + (i + 1));
		}
		for(int i = 0; i < h; i++) {
			for(int j = 0; j < ver[i]; j++) {
				out.println("row " + (i + 1));
			}
		}
	}
	
}

class Writer extends PrintWriter{
	public Writer(String filename)throws IOException
	{super(new BufferedWriter(new FileWriter(filename)));}
	public Writer()throws IOException{super(System.out);}
}
class ContestScanner implements Closeable{
	private BufferedReader in;private int c=-2;
	public ContestScanner()throws IOException 
	{in=new BufferedReader(new InputStreamReader(System.in));}
	public ContestScanner(String filename)throws IOException
	{in=new BufferedReader(new InputStreamReader(new FileInputStream(filename)));}
	public String nextToken()throws IOException {
		StringBuilder sb=new StringBuilder();
		while((c=in.read())!=-1&&Character.isWhitespace(c));
		while(c!=-1&&!Character.isWhitespace(c)){sb.append((char)c);c=in.read();}
		return sb.toString();
	}
	public String readLine()throws IOException{
		StringBuilder sb=new StringBuilder();if(c==-2)c=in.read();
		while(c!=-1&&c!='\n'&&c!='\r'){sb.append((char)c);c=in.read();}
		return sb.toString();
	}
	public long nextLong()throws IOException,NumberFormatException
	{return Long.parseLong(nextToken());}
	public int nextInt()throws NumberFormatException,IOException
	{return(int)nextLong();}
	public double nextDouble()throws NumberFormatException,IOException 
	{return Double.parseDouble(nextToken());}
	public void close() throws IOException {in.close();}
}